Lignocellulosic Nanomaterial in an Oil-in-Water Emulsion Fluid System with or without an Emulsifier Sucrose Ester

Abstract

The effect of lignocellulosic nanomaterial (LCNM) including lignin-containing cellulose nanofibers (LCNFs) and cellulose nanofibers (CNFs) on a diesel oil-in-water (O/W) emulsion was investigated with and without the emulsifier sucrose ester (SE). The O/W (65:35) emulsions were successfully stabilized by LCNFs with two lignin levels, while emulsions with CNFs exhibited large fiber flocs in the external phase only. High-lignin-content LCNFs led to a more uniform oil droplet size without formation of fiber flocs, whereas low-lignin-content LCNFs in emulsion revealed a wide size distribution of the oil droplets with intensive fiber flocs. The presence of SE significantly enhanced the stability of LCNM emulsions, reducing the size of oil droplets with a more uniform distribution and facilitating the dispersion of fiber components. The gelation properties, in turn, were markedly reduced by SE. The overall rheological properties were more dominated by the intrinsic characteristics of LCNM. Significant improvements in filtration performance with bentonite added to emulsion fluids were observed via applying SE into the emulsion system. The synergy between LCNFs and SE, along with the potential for diverse applications, opens a pathway for a sustainable emulsion technology toward greener, more effective, and economically viable emulsion systems.